The present invention relates to projection systems where multiple projectors are utilized to create respective complementary portions of a projected image, which may be a video or still image. The present invention also relates to methods of calibrating the intensity response function of projectors. According to one embodiment of the present invention, a method of projecting an image utilizing a plurality of projectors is provided. According to the method, at least two of the projectors project overlapping portions of the image in a global display space. Overlapping pixels in the global display space are identified. An attenuation map is generated for the projectors such that the attenuation values for the overlapping pixels of the attenuation map are at least partially a function of the number of projectors contributing to the overlap. Pixel intensity values are established for the projectors by applying one or more intensity transfer functions to the attenuation maps generated for the projectors. The intensity transfer functions may be applied to the attenuation maps in conjunction with input intensity values. The intensity transfer functions are configured to at least partially account for the non-linear response of the output intensity of the projectors, as a function of an input intensity control signal applied to the projectors.
In accordance with another embodiment of the present invention, pixel intensity values for the projectors are established by utilizing the attenuation maps such that the pixel intensity values are a function of the relative magnitudes of the distance-to-edge values for the edges of the projectors that overlap the selected pixel.
In accordance with yet another embodiment of the present invention, pixel intensity values are established for the projectors by perturbing the attenuation maps to reduce image artifacts in the image, such that the pixel intensity values are a function of an attenuation map perturbation routine.
In accordance with yet another embodiment of the present invention, a method of calibrating the intensity response function of a projector or operating the image projector according to a calibrated intensity response function is provided. According to the method, a calibration image comprising an intensity-adjusted portion and a dithered portion is generated. Pixels of the intensity-adjusted portion are driven at a fraction of maximum input intensity and the ratio of the on/off pixels in the dithered portion is selected to correspond to the fractional input intensity of the intensity-adjusted portion. Pixel intensity in either the intensity-adjusted portion or the dithered portion is adjusted to match the apparent intensity of the remaining portion. This pixel intensity adjustment is repeated for one or more additional fractional input intensities and the intensity adjustments are used to establish a calibrated intensity response function for the image projector. The intensity transfer function is configured to at least partially account for the non-linear response of the output intensity of the projector as a function of an input intensity control signal applied to the projector.